package com.principle.strategy;

public abstract class Duck {

    abstract void display();
    public void quack(){
        System.out.println("鸭子嘎嘎叫");
    }
    public void swim(){
        System.out.println("鸭子会游泳");
    }
    public void fly(){
        System.out.println("鸭子会飞");
    }
}
